//--------------------------------------------------------------------------
//	Copyright (c) 1998-2004, Drew Davidson and Luke Blanshard
//  All rights reserved.
//
//	Redistribution and use in source and binary forms, with or without
//  modification, are permitted provided that the following conditions are
//  met:
//
//	Redistributions of source code must retain the above copyright notice,
//  this list of conditions and the following disclaimer.
//	Redistributions in binary form must reproduce the above copyright
//  notice, this list of conditions and the following disclaimer in the
//  documentation and/or other materials provided with the distribution.
//	Neither the name of the Drew Davidson nor the names of its contributors
//  may be used to endorse or promote products derived from this software
//  without specific prior written permission.
//
//	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
//  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
//  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
//  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
//  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
//  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
//  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
//  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
//  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
//  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
//  DAMAGE.
//--------------------------------------------------------------------------
package com.feilong.lib.ognl;

import java.util.*;

/**
 * A Map that uses ints as the keys.
 * <p>
 * Use just like any java.util.Map, except that the keys must be ints.
 * This is much faster than creating a new Integer for each access.
 * </p>
 * <p>
 * For non-Map access (faster) use the put(int, Object) method.
 * </p>
 * <p>
 * This class implements Map for convenience, but this is not the most
 * efficient usage.
 * </p>
 * 
 * @see java.util.HashMap
 * @see java.util.Map
 */
public class IntHashMap extends Object implements Map{

    private Entry table[];

    private int   count;

    private int   threshold;

    private float loadFactor;

    /*
     * ===================================================================
     * Private static classes
     * ===================================================================
     */
    private static class IntHashMapIterator implements Iterator{

        boolean keys;

        int     index;

        Entry   table[];

        Entry   entry;

        IntHashMapIterator(Entry table[], boolean keys){
            super();
            this.table = table;
            this.keys = keys;
            this.index = table.length;
        }

        /*
         * ===================================================================
         * Iterator interface
         * ===================================================================
         */
        @Override
        public boolean hasNext(){
            if (entry != null){
                return true;
            }
            while (index-- > 0){
                if ((entry = table[index]) != null){
                    return true;
                }
            }
            return false;
        }

        @Override
        public Object next(){
            if (entry == null){
                while ((index-- > 0) && ((entry = table[index]) == null)){
                    /* do nothing */
                }
            }
            if (entry != null){
                Entry e = entry;

                entry = e.next;
                return keys ? new Integer(e.key) : e.value;
            }
            throw new NoSuchElementException("IntHashMapIterator");
        }

        @Override
        public void remove(){
            throw new UnsupportedOperationException("remove");
        }
    }

    /*
     * ===================================================================
     * Public static classes
     * ===================================================================
     */
    public static class Entry extends Object{

        int    hash;

        int    key;

        Object value;

        Entry  next;

        public Entry(){
            super();
        }
    }

    /*
     * ===================================================================
     * Constructors
     * ===================================================================
     */
    public IntHashMap(int initialCapacity, float loadFactor){
        super();
        if (initialCapacity <= 0 || loadFactor <= 0.0){
            throw new IllegalArgumentException();
        }
        this.loadFactor = loadFactor;
        table = new Entry[initialCapacity];
        threshold = (int) (initialCapacity * loadFactor);
    }

    public IntHashMap(int initialCapacity){
        this(initialCapacity, 0.75f);
    }

    public IntHashMap(){
        this(101, 0.75f);
    }

    /*
     * ===================================================================
     * Protected methods
     * ===================================================================
     */
    protected void rehash(){
        int oldCapacity = table.length;
        Entry oldTable[] = table;
        int newCapacity = oldCapacity * 2 + 1;
        Entry newTable[] = new Entry[newCapacity];

        threshold = (int) (newCapacity * loadFactor);
        table = newTable;
        for (int i = oldCapacity; i-- > 0;){
            for (Entry old = oldTable[i]; old != null;){
                Entry e = old;
                int index = (e.hash & 0x7FFFFFFF) % newCapacity;

                old = old.next;
                e.next = newTable[index];
                newTable[index] = e;
            }
        }
    }

    /*
     * ===================================================================
     * Public methods
     * ===================================================================
     */
    public final boolean containsKey(int key){
        int index = (key & 0x7FFFFFFF) % table.length;

        for (Entry e = table[index]; e != null; e = e.next){
            if ((e.hash == key) && (e.key == key)){
                return true;
            }
        }
        return false;
    }

    public final Object get(int key){
        int index = (key & 0x7FFFFFFF) % table.length;

        for (Entry e = table[index]; e != null; e = e.next){
            if ((e.hash == key) && (e.key == key)){
                return e.value;
            }
        }
        return null;
    }

    public final Object put(int key,Object value){
        int index = (key & 0x7FFFFFFF) % table.length;

        if (value == null){
            throw new IllegalArgumentException();
        }
        for (Entry e = table[index]; e != null; e = e.next){
            if ((e.hash == key) && (e.key == key)){
                Object old = e.value;

                e.value = value;
                return old;
            }
        }

        if (count >= threshold){
            // Rehash the table if the threshold is exceeded.
            rehash();
            return put(key, value);
        }

        Entry e = new Entry();

        e.hash = key;
        e.key = key;
        e.value = value;
        e.next = table[index];
        table[index] = e;
        ++count;
        return null;
    }

    public final Object remove(int key){
        int index = (key & 0x7FFFFFFF) % table.length;

        for (Entry e = table[index], prev = null; e != null; prev = e, e = e.next){
            if ((e.hash == key) && (e.key == key)){
                if (prev != null){
                    prev.next = e.next;
                }else{
                    table[index] = e.next;
                }
                --count;
                return e.value;
            }
        }
        return null;
    }

    /*
     * ===================================================================
     * Map interface
     * ===================================================================
     */
    @Override
    public int size(){
        return count;
    }

    @Override
    public boolean isEmpty(){
        return count == 0;
    }

    @Override
    public Object get(Object key){
        if (!(key instanceof Number)){
            throw new IllegalArgumentException("key is not an Number subclass");
        }
        return get(((Number) key).intValue());
    }

    @Override
    public Object put(Object key,Object value){
        if (!(key instanceof Number)){
            throw new IllegalArgumentException("key cannot be null");
        }
        return put(((Number) key).intValue(), value);
    }

    @Override
    public void putAll(Map otherMap){
        for (Iterator it = otherMap.keySet().iterator(); it.hasNext();){
            Object k = it.next();

            put(k, otherMap.get(k));
        }
    }

    @Override
    public Object remove(Object key){
        if (!(key instanceof Number)){
            throw new IllegalArgumentException("key cannot be null");
        }
        return remove(((Number) key).intValue());
    }

    @Override
    public void clear(){
        Entry tab[] = table;

        for (int index = tab.length; --index >= 0;){
            tab[index] = null;
        }
        count = 0;
    }

    @Override
    public boolean containsKey(Object key){
        if (!(key instanceof Number)){
            throw new InternalError("key is not an Number subclass");
        }
        return containsKey(((Number) key).intValue());
    }

    @Override
    public boolean containsValue(Object value){
        Entry tab[] = table;

        if (value == null){
            throw new IllegalArgumentException();
        }
        for (int i = tab.length; i-- > 0;){
            for (Entry e = tab[i]; e != null; e = e.next){
                if (e.value.equals(value)){
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public Set keySet(){
        Set result = new HashSet();

        for (Iterator it = new IntHashMapIterator(table, true); it.hasNext();){
            result.add(it.next());
        }
        return result;
    }

    @Override
    public Collection values(){
        List result = new ArrayList();

        for (Iterator it = new IntHashMapIterator(table, false); it.hasNext();){
            result.add(it.next());
        }
        return result;
    }

    @Override
    public Set entrySet(){
        throw new UnsupportedOperationException("entrySet");
    }
}
